Esters of cis-3-(haloalkenyl)-2,2-dimethylcyclopropanecarboxylic acid with 4-methyl-2,3,5,6-tetrafluorophenyl alcohol, in particular tefluthrin [2,3,5,6-tetrafluoro-4-benzyl-cis-((Z)-2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethyl-cyclopropane carboxylate], are important insecticidal and acaricidal products. It is thus desired to provide an industrially acceptable and efficient process for making the necessary intermediates such as 2,3,5,6-tetrafluorodimethylolbenzene.
Known processes for preparing 2,3,5,6-tetrafluorodimethylolbenzene are described in some patents. However, further alternative processes that give high quality product in good yield are still required for the production of 2,3,5,6-tetrafluorodimethylolbenzene on an industrial scale.